There are quite a few actually to choose from. Kinda hard to pick just one so I'll name a few that are pretty good at what they do.
1. Rockstar. Read Dead Redemption style was something totally unheard of in modern gaming. The formula was similar to GTA, however, the voice acting, story, pacing, was amazing. Actually felt you lived through John Marston at times and was living in the wild west. Beautifully done. Infact I rate RDR higher than the GTA series and among their best work. I just think GTA is beautifully done for an open world game but its RDR that truly deserves the praise.
2. Bethesda. Skyrim - Enough said. If that was their only game, it would be their legacy. They would still be remebered for designing a world so immersive and so intriquing and captivating where hours just seem to pass by and you just want to keep exploring every nook and cranny and then you have dragons as well. But that isn't so. They've made some of the best RPGs of this generation.
3. Rocksteady - Totally surprised no one has mentioned these guys. I get it this is a very PC heavy community but still its not like the games ain't avaiable on steam. They were pretty much unknowns when they took on the project of the Batman series. There were so many studios that have worked on comic book games and failed to deliver. These guys delivered and more. Now I've never really been a big Batman fan or a comic book fan. But these folks totally changed everything about it. You see Batman as an individual and you see a very different side to him. The Arkhym series will go down as the best in the action - adventure genre and one of the best in video gaming. The combat is freaking fluid, never played a game with such fluid combat. The characters are fun and the voice acting - omg. The best I've seen in a game and that says a lot. If it was a movie, a few guys would deservedly be nomiated for an oscar. The open world feeling in Arhym City is pretty good. The story, plot, action, you name it, its all very well done. The whole game is packaged with little to no bugs and its quite an undertaking.